Authorities yesterday raised the alarm over high levels of air pollution in seven northern provinces.
Air quality is bad in Chiang Mai's Mae Chaem district and Lampang's Muang district, according to Chayaphon Thitisak, chief of the Disaster Prevention and Mitigation Department.
At 3pm yesterday, the level of PM2.5 in parts of Mae Chaem rose alarmingly to 105 microgrammes per cubic metre (µg/m³), which is significantly higher compared to the "safety" limit of 50 µg/m³, according to the Pollution Control Department's Air4Thai, its air quality monitoring application.
Levels of the larger PM10 particle dust which often spreads due to construction activities was measured at 126 µg/m³, which is over the PCD's acceptable level of 120 µg/m³.
Tambon Phra Bat in Lampang's Muang district had 91 µg/m³ of PM2.5.
So far this year, the northern region has suffered from air pollution caused by fires set by farmers to clear land for harvesting. Also, weather patterns have only worsened the situation as stagnant air during this time of year prevents smog from dissipating to higher altitudes.
Another five provinces -- Lamphun, Mae Hong Son, Nan, Phrae and Tak -- also found themselves facing similar problems, according to Mr Chayaphon.
Villagers need to wear face masks when venturing outside their homes. Meanwhile, local officials must spray water to reduce dust levels.
Provinces in the Northeast are still suffering from air pollution as well.
Among them is Nakhon Ratchasima, where PM2.5 levels yesterday rose to 48 µg/m³ and PM10 to 79 µg/m.³ Air pollution in the Northeast is a result of open burning to clear land for corn harvesting and for construction of a high-speed train project.
However, air quality in Bangkok improved as PM2.5 along Rama IV Road in the evening was only 19 µg/m.³
But Wijarn Simachaya, permanent secretary for the Natural Resources and Environment Ministry urged people not to be complacent.
"It can return in the future," he said yesterday at a seminar on long-term solutions to urban air pollution.